Tubular member deformable into a bellows for sealing a reciprocating rod

Abstract

A tubular member comprises a tubular body made of rubber. The tubular body has a base portion, a head portion, and a plurality of annular grooves or annular projections formed in an inner wall of the body. The base portion is arranged to be secured to a guide member of an actuator, and the head portion is arranged to be engaged with a rod slidably supported in the guide member.

What is claimed is: 
     
       1. A tubular member made of rubber for sealing a reciprocating rod comprising: a tubular body having a right cylinder portion in a free form condition which is slidably engaged with the reciprocating rod, a base portion, a head portion, and a plurality of annular portions formed in the right cylinder portion and disposed in the axial direction thereof, the thickness of each annular portion being different from that of the right cylinder portion, so that a plurality of thin portions are formed in the right cylinder portion;   the base portion being arranged to be secured to a guide member of an actuator;   the head portion being arranged to be engaged with a reciprocating rod slidably supported in the guide member;   the annular portions being so designed that, when the rod is retracted in the guide member to contract the right cylinder portion, each of the thin portions is outwardly projected from the reciprocating rod to form a U-shaped section both sides of which are closely contacted with each other and that adjacent U-shaped portions are also closely contacted with each other.   
     
     
       2. The tubular member according to claim 1 wherein each of said annular portions is an annular groove formed in an inner wall of the tubular body. 
     
     
       3. The tubular member according to claim 1 wherein each of said annular portions is an annular projecting rib formed on an inner wall of the tubular body. 
     
     
       4. The tubular member according to claim 1 wherein each of said annular portions is an annular projecting rib formed on an outer periphery of the tubular body. 
     
     
       5. The tubular member according to claim 1 wherein said head portion has a closed head. 
     
     
       6. The tubular member according to claim 1 wherein said head portion has an open head. 
     
     
       7. The tubular member according to claim 1 wherein each of said thin portions is formed with an annular groove on an inner wall which has an arcuate section in longitudinal section of the right cylinder portion, and an annular projection having a V-shaped section is formed between adjacent annular grooves defining said annular portion.